Overview: The Fii O E1 is a headphone amplifier, specifically designed for use with Apple’s iPod & iPhone It is the first headphone amplifier in the world with in-line remote control functions The Fii O E1 has a built in high quality headphone amplifier IC manufactured by Texas Instruments The Fii O E1 uses the line out signal from the iPod/iPhone, so it provides better sound quality, & is able to drive high impedance or low sensitivity headphones With the in-line control function, you can easily control the playback of the iPod/iPhone from the E1 Amplifier The Fii O E1 will bring you better sound quality & a more convenient playback experience Designed for iPod/iPhone Improves the sound quality with the line out from the dock Build in high quality Texas Instruments’s headphone amplifier Integrated Circuit High power output to drive high impedance or low sensitivity headphones or earphones Easy control of the playback of the iPod/iPhone while the player stays securely in your pocket Compatible with iPod Nano, iPod Video, iPod Touch, iPhone, all generations & all versions Easy & simple to use, plug & play Powered by the iPod/iPhone (no charging or battery needed) Traditional Apple white style, with a built-in clip, you can clip it onto anything Specification: Dimensions:31.5in*1.38in*0.39in Weight:0.51oz